This view of the twilight sky and Martian horizon taken by NASA's Curiosity Mars rover includes Earth as the brightest point of light in the night sky. Earth is a little left of center in the image, and our moon is just below Earth.

This frame from an animation from NASA's Mars rover Curiosity shows the rover drilling into rock target 'Cumberland.' The drilling was performed during the 279th Martian day, or sol, of the Curiosity's work on Mars (May 19, 2013).

This image from the Mars Hand Lens Imager on NASA's Mars rover Curiosity shows the patch of rock cleaned by the first use of the rover's Dust Removal Tool (DRT). The tool is a motorized, wire-bristle brush on the turret at the end of the rover's arm.

The two bodies in this portion of an evening-sky view by NASA's Mars rover Curiosity are Earth and Earth's moon. The rover's Mast Camera (Mastcam) imaged them in the twilight sky of Curiosity's 529th Martian day, or sol (Jan. 31, 2014).

NASA's Curiosity rover and its parachute were spotted by NASA's Mars Reconnaissance Orbiter as Curiosity descended to the surface on Aug. 5 PDT (Aug. 6 EDT). Curiosity and its parachute are in the small white box at center.

This labeled version of one of the first images taken by a rear Hazard-Avoidance camera on NASA's Curiosity rover shows a fin on the radioisotope thermoelectric generator, the rear left wheel and a spring that released the dust cover.

NASA's Curiosity rover and its parachute were spotted by NASA's Mars Reconnaissance Orbiter as Curiosity descended to the surface on Aug. 5 PDT (Aug. 6 EDT). Curiosity and its parachute are in the center of the white box.

NASA's Curiosity rover and its parachute were spotted by NASA's Mars Reconnaissance Orbiter as Curiosity descended to the surface. The HiRISE camera captured this image of Curiosity while the orbiter was listening to transmissions from the rover.

NASA's Curiosity rover and its parachute were spotted by NASA's Mars Reconnaissance Orbiter as Curiosity descended to the surface. The HiRISE camera captured this image of Curiosity while the orbiter was listening to transmissions from the rover.

This is a version of one of the first images taken by a front Hazard-Avoidance camera on NASA's Curiosity rover. It was taken through a "fisheye" wide-angle lens but has been "linearized" so that the horizon looks flat rather than curved.

This is a version of one of the first images taken by a front Hazard-Avoidance camera on NASA's Curiosity rover. It was taken through a "fisheye" wide-angle lens but has been "linearized" so that the horizon looks flat rather than curved.

This is a version of one of the first images taken by a rear Hazard-Avoidance camera on NASA's Curiosity rover and shows part of the rim of Gale Crater, which is a feature the size of Connecticut and Rhode Island combined.

This is a version of one of the first images taken by a rear Hazard-Avoidance camera on NASA's Curiosity rover and shows part of the rim of Gale Crater, which is a feature the size of Connecticut and Rhode Island combined.

This is one of the first images taken by NASA's Curiosity rover, which landed on Mars the evening of Aug. 5 PDT (morning of Aug. 6 EDT). The clear dust cover that protected the camera during landing has been sprung open.

This is the first image taken by NASA's Curiosity rover, which landed on Mars the evening of Aug. 5 PDT (morning of Aug. 6 EDT). It was taken through a "fisheye" wide-angle lens on one of the rover's rear right Hazard-Avoidance cameras.

This is the first image taken by NASA's Curiosity rover, which landed on Mars the evening of Aug. 5 PDT (morning of Aug. 6 EDT). It was taken through a "fisheye" wide-angle lens on one of the rover's rear left Hazard-Avoidance cameras.

This is the first image taken by NASA's Curiosity rover, which landed on Mars the evening of Aug. 5 PDT (morning of Aug. 6 EDT). It was taken through a "fisheye" wide-angle lens on one of the rover's front right Hazard-Avoidance cameras.

This is the first image taken by NASA's Curiosity rover, which landed on Mars the evening of Aug. 5 PDT (morning of Aug. 6 EDT). It was taken through a "fisheye" wide-angle lens on one of the rover's front left Hazard-Avoidance cameras.

This global map of Mars was acquired on Aug. 4, 2012, by the Mars Color Imager instrument on NASA's Mars Reconnaissance Orbiter to forecast weather conditions for the entry, descent and landing of NASA's Curiosity rover.

This frame from an artist's animation depicts how NASA's Curiosity rover will communicate with Earth during landing. As the rover descends to Mars, it will send out basic radio-frequency tones that go directly to Earth.

This global map of Mars was acquired on Aug. 2, 2012, by the Mars Color Imager instrument on NASA's Mars Reconnaissance Orbiter. One global map is generated each day to forecast weather conditions for the entry, descent and landing of NASA's Curiosity.

This global map of Mars was acquired on Oct. 28, 2008, by the Mars Color Imager instrument on NASA's MRO. One global map is generated each day to forecast weather conditions for the entry, descent and landing of NASA's Curiosity rover.

Gale Crater on Mars, where NASA's Curiosity rover is set to land, belongs to a family of large, very old craters shown here on this elevation map. The data come from the Mars Orbiter Laser Altimeter instrument on NASA's Mars Global Surveyor.